Fig. 6From: Optimized electroencephalogram and functional near-infrared spectroscopy-based mental workload detection method for practical applicationsChanges of blood oxygen under different load levels. The left and right images represent the left and right sides of the forehead, with O2HB changes on the upper side and HHB changes on the lower side. Note that the * means p_FDR < 0.05, ** means p_FDR < 0.01Back to article page